Power distribution units (PDUs) have been employed to supply power to electronic equipment in racks and to remotely monitor and control the supply of power to the equipment. A conventional power distribution unit is an assembly of multiple electrical outlets (i.e. receptacles) that receive electrical power from a power source and distribute the electrical power via the plural outlets to the electronic equipment, for example data-processing equipment having respective power cords being plugged into respective outlets of the power distribution unit. The power distribution unit further includes a power management circuitry that can power-on and power-off the power outlets in accordance with an administrator defined sequence and delays. The power management circuitry can further sense electrical current drawn by the electronic equipment and control operation of the power distribution unit based on the sensed electrical current. The power distribution unit can be used in any of various applications and setting such as, for example, in or on electronic equipment racks, among other applications. The power distribution unit located in a cabinet may be used to control other devices such as environmental sensors, for example temperature sensors and humidity sensors, fuse module or communication modules and the like. A plurality of PDUs and other devices to which it is connected are commonly enclosed within an equipment rack or equipment cabinet.
The power distribution units, which are enclosed within an equipment rack or located at different equipment racks, are capable of directly communicating with a remote management system (RMS) via a network. The RMS sends/receives communication data, commands or information to/from the power distribution units through IP communication protocol with a unique IP address for each PDU. A conventional topology for power management device is given in U.S. Patent Publication No. 2007/0140238 to Ewing et al. The representative figure of this prior art reference is depicted as FIG. 1 of the invention. FIG. 1 shows a remote management system employed for coupling with and managing a plurality of PDUs. A remote management system (RMS) may be configured for various kinds of user interactions. Generally, the RMS is provided as an Internet-based application that communicates with client browsers through web server. Each PDU may comprise one or more electrical outlets and sensors that indicate voltage present at the outlets and current flow through each outlet. Each PDU may transmit the operational data or power consumption information of each outlet to the RMS via the network 102 so that RMS can manage and control the operations of the PDUs based on the data or information.
Please refer to FIG. 1 again. The power management system 100 includes a RMS including a host system 101 connected over a network 102 to a controlled system 103 including one or more PDUs and computer-based appliances. A power manager circuit 104, e.g., power distribution unit (i.e. power distribution strip), is used to monitor and control the operating power supplied to a plurality of computer-based appliances 105 associated with a network interface. The role and purpose of the power management system 100 is to monitor the power and environmental operating conditions in which the computer-based appliances 105 operate, and to afford management personnel the ability to turn the computer-based appliances 105 on and off from the host system 101. Such power-cycling allows a power-on rebooting of software in the computer-based appliances 105 to be forced without actually having to visit the site. The operating conditions and environments are preferably reported to the host system 101 on request and when alarms occur.
The power manager circuit 104 (i.e. PDU) further comprises a network interface 1041 and this may be connected to a security device 1042. If the network 102 is the internet, the security device 1042 can provide protection of a protocol stack 1043 from accidental and/or malicious attacks. The protocol stack 1043 is coupled to a power manager 1044, and it converts software commands communicated to the form of IP data packets 106 that the power manager 1044 can use. For example, message can be sent from the host system 101 that will cause the power manager 1044 to operate the relay-switch 1045. In reverse, voltage, current and temperature information collected by the sensors 1046 are collected by the power manager 1044 and encoded by the protocol stack 1043 into appropriate data packets 106. Locally, a keyboard 1047 can be used to select a variety of readouts on a display 1048, and also to control the relay-switch 1045.
Currently, the RMS uses IP networks to manage a multiplicity of PDUs. Namely, all alarm, events, and commands are sent/received between RMS and each individual PDU and connect them with IP networks. This approach will result in a very long response time because RMS has to receive all the operational data or power consumption information about the outlets of the PDUs from the PDUs and check each PDU and other power device in a round-robin or prioritized round-robin style. In addition, the data processing burden on the RMS will be increased and the physical connections between the PDUs with the network will be complex and costly.
To overcome the disadvantages of the prior art described above, the present invention provides a local power management unit and a power management system employing the same.